Acetoacet-methine color formers



Patented Sept. 23, 1947 ACETOACET-METHINE COLOR FORMERS John DavidKendall and Douglas James Fry, Ilford, England, assignors to IlfordLimited, Ilford, England, a British company No Drawing. Application May3, 1945, Serial No. 591,829. In Great Britain May 12, 1944 8 Claims.

Thisinvention relates to colour photography and particularly to dyestuffintermediates for use in colour photographic processes.

Processes of colour photography are well known in which coloured imagesare producedby the development of reducible silver salt images by meansof aromatic primary amino developing agents in the presence ofcompounds, generally known as colour-formers r colour-couplers, whichcouple with the oxidation products of such developers, formed duringdevelopment, to form quinone-imine or azomethine dyes. Thecolourcouplers may be present in the developing solution employed, ormay be included in a photographic emulsion layer which contains thereducible silver salt image, or in an adjacent layer or a layerseparated from the said emulsion layer only by a thin water-permeablelayer. The developing agent may be, for example, p-phenylene diamine orits N.N.-dialky1 derivatives, e. g. N.N.-dimethyl and N.N.-diethylp-phenylene diamines, and homologues thereof and5-diethylamino-Z-amino-toluene.

Large numbers of colour-couplers have been described in the extensiveliterature dealing with this type of colour photographic process. Therequirements for a satisfactory colour-coupler, however, are ratherstrict. Thus it must be capable of ready incorporation into thedeveloping bath or photographic layer into which it is desired toinclude it, and where it is included in a photographic layer, neither itnor the dye derived from it must have any substantial tendency todiffuse from such layer, either into adjacent layers of the photographicelement, or into processing baths. Moreover, it must be selected so thatthe colour of the dye obtained from it is suitable for the particularcolour process with which it is intended to be used.

According to the present invention a process of colour photographycomprises developing a reducible silver salt image by means of anarcmatic primary amino developing agent in the presence of a compound ofthe general formula:

where D is the residue of a heterocyclic nitrogen nucleus, n is aninteger less than 3, R1 is a hydrocarbon or heterocyclic group, and R2is an alkyl or aralkyl group.

The heteroclyclic nucleus may be five-membered or six-membered. Examplesare thiazoles, oxazoles, selenazoles and their polycyclic homologues,such as those of the benzene and naphthalene series, pyridine and itspolycyclic homologues, such as quinoline and a and fl-naphthoquinolines,lepidines, picolines, indolenines, diazines (e. g., thio pp diazoleoxazolines, thiazolines and selenazolines. The polycyclic compounds ofthis series may be substituted in the carbocyclic rings with one or moregroups such as alkyl, aryl, amino, hydroxy, alkoxy and methylene-dioxygroups, or by halogen atoms.

The group R1 may be an alkyl, aryl or aralkyl group, e. g., methyl,ethyl or higher alkyl; phenyl or naphthyl; or benzyl or naphthylmethyl.Or R1 may be a heterocyclic group, e. g., a furoyl, coumaryl,thionaphthenyl or a residue of any of the heterocyclic nitrogencompounds referred to above. R2 may be any of the alkyl or aralkylgroups referred to above.

The compounds employed in accordance with the present invention may beprepared by any convenient method. One suitable method is to condense aheterocyclic nitrogen quaternary salt containing a methyl group in or or7 position to the quaternary nitrogen atom with an acyl acetic ester inthe presence of a solvent and a base. Thus, for example, l-aceto acetylmethine-2- methyl benzthiazole may be prepared by refluxing l-methylbenzthiazole methiodid with acetoacetic ester in the presence of xyleneas solvent and in the presence of a small quantity of triethylenine orother base, e. g., sodium ethoxide. Under these conditions the alcoholliberated in the reaction may be distilled off and the residue, afterfiltering, removal of the xylene and recrystallisation, is the desiredproduct. This product, M. Pt. 124 0., yields a strong yellow image oncolour-coupling development in accordance with this invention, and theimage is strongly resistant to sulphite, i. e., its depth is notsubstantially reduced by the presence of sulphite in the developer used.

Other compounds for use in the present invention may be prepared fromquaternary'salts of any of the heterocyclic nitrogen compounds referredto above, which contain a methyl group in the a or 7 position to thequaternary nitrogen atom. Instead of aceto acetic ester there may beemployed: ethyl benzoylacetate, ethyl furoylacetate, ethylpicolinoylacetate and similar compounds.

Particular compounds of use in the present invention are:

l-acetoacet-methine-Z-methyl--6-dihydronaphtha-thinzole (prepared from)ethyl acetoacetatc and 1-methyl-5.6-naphthath1azole ethrodide N (IDHE2-acetoacet-methine-3:4-dirncthyl thiazolino (prepared from ethylacetoacetate and 2.4-dimethyl thiazole methiodide) CHz- S l C=CHCO-CH2COCH5 CHs- H--N (5H:l-acetoacet-mcthine-2-methyldihydrobenzthiazole (prepared from ethylacetoacetatc and l-methyl-benzthiaz ole methiodide)2-benzoylacct-methine-l-methyl-dihydroquinolinc (prepared from ethylbenzoylacetntc and quinal dine methiodlde)1-Iuroylacet-methine-2-ethyl-4-chlorodihydrobenzthiozole (prepared iron:ethyl furoyl-acetate and l-methyli-chlor-benzthiazole ethiodie""""1-picolinoylacet-methine-2-ethyl-4-methyl-dihydrobenzthiazo]e (prepagedd{10311 ethyl picolinoylacetate and 1:4-dimethy] benzthlazole et io e Vr 4 2,369,171, and British Patents Nos. 551,117, 554,302 and 556,858.

The formation of coloured images by means of the colour-couplers of thisinvention may be applied to the development of a reducible silver saltimage which is an original latent image formed in the emulsion layer byexposure to light, or which is an image obtained by the conversion of asilver image to a reducible silver salt image by the usual bleachingtechnique.

Although this invention is primarily concerned with colour photographicprocesses in which the dye is formed by the coupling of thecolour-couplers of the invention with the oxidation products of anaromatic primary amino developing agent formed in situ during thedevelopment of a reducible silver salt image, the colour-couplers of theinvention may also be employed in other colour photographic processes,e. g., processes in which the dye is formed by direct coupling betweenthe colour-coupler and a nitroso anilene, e; g., p-nitroso dialkylanilene, or between the colour-coupler and a diazo compound. As anexample of this latter type of process a colourcoupler may be present ina layer containing a reducible silver salt image, such image developedwith an aromatic primary amino developing agent forming an azomethinedye image in situ with the developed silver image, the residualcolour-coupler coupled with a diazo compound applied in solution to thphotographic element, and the original azomethine dye image bleachedout, leaving only the azo dye image in the layer.

What We claim is:

1. A process of colour photography which comprises developing areducible silver salt image in a photographic element by means of anaromatic primary amino developing agent in the presence of a compound ofthe general formula:

where D is the residue of a heterocyclic nitrogen nucleus, n is aninteger less than 3, R1 is a group selected from the class consisting ofhydrocarbon and heterocyclic groups, and R2 is a group selected from theclass consisting of alkyl and aralkyl groups.

' '2. A process of colour photography which comprises developinga'reducible silver salt in a photographic element by means of a solutionof an aromatic primary amino developing agent containing a compound ofthe general formula:

where D is the residue ofa heterocyclic nitrogen nucleus, 11. is aninteger less than 3, R1 is a group selected from the class consisting ofhydrocarbon and heterocyclic groups, and R2 is a group selected from theclass consisting of alkyl and aralykyl groups.

3. A photogrphic element for colour photography which comprises asupport bearing at least one layer of a light-sensitive silver halideemulsion containing a compound of the general formula:

where D is the residue of a heterocyclic nitrogen nucleus, n is aninteger less than 3, R1 is a group selected from the class consisting ofhydrocarbon and heterocyclic groups, and R2 is a group selected from theclass consisting of alkyl and aralkyl groups.

4. A photographic element for colour photography which comprises asupport hearing at least one layer of a light-sensitive silver halideemul sion and, adjacent thereto, a layer containing a compound of thegeneral formula:

where D is the residue of a heterocyclic nitrogen nucleus, n is aninteger less than 3, R1 is a group selected from the class consisting ofhydrocarbon and heterocyclic groups, and R2 is a group selected from theclass consisting of alkyl and aralkyl groups.

5. A process of colour photography which comprises forming a reduciblesilver salt image in an emulsion layer of a photographic element whichcontains a compound of the general formula:

where D is the residue of a heterocyclic nitrogen nucleus, 11 is aninteger less than 3, R1 is a group selected from the class consisting ofhydrocarbon and heterocyclic groups, and R2 is a group selected from theclass consisting of alkyl and aralkyl groups, and developing said imagewith an aromatic primary amino developing agent.

6. A process of colour photography which comprises forming a reduciblesilver salt image in an emulsion layer of a photographic element whichcontains a compound of the general formula:

where D is the residue of a heterocyclic nitrogen nucleus, n is aninteger less than 3, R1 is a group selected from the class consisting ofhydrocarbon and heterocyclic groups, and R2 is a group selected from theclass consisting of alkyl and aralkyl groups, and developing said imagewith an N,N-dialkyl-p-phenylene diamine.

7. A process of colour photography which comprises forming a reduciblesilver salt image in an emulsion layer of a photographic element whichincludes, adjacent thereto, a layer containing a compound of the generalformula:

where D is the residue of a heterocyclic nitrogen nucleus, in is aninteger less than 3, R1 is a group selected from the class consisting ofhydrocarhon and heterocyclic groups, and R2 is a group selected from theclass consisting of alkyl and aralkyl groups, and developing said imagewith an aromatic primary amino developing agent.

8. A process of colour photography which comprises forming a reduciblesilver salt image in an emulsion layer of a photographic element whichincludes, adjacent thereto, a layer containing a compound of the generalformula:

where D is the residue of a heterocyclic nitrogen nucleus, n is aninteger less than 3, R1 is a group selected from the class consisting ofhydrocarbon and heterocyclic groups, and R2 is a group selected from theclass consisting of alkyl and aralkyl groups, and developing said imagewith an N,N-dialkyl-pphenylene diamine.

JOHN DAVID KENDALL.

DOUGLAS JAMES FRY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date Schwarc Nov. 5, 1940 Kendall et a1, Feb.23, 1943 Kirby et a1. Sept. 7, 1943 FOREIGN PATENTS Country Date GreatBritain Oct. 17, 1939 Number Number

